In recent years, a processing method called remote laser processing has drawn attention, which performs laser welding by irradiating a processing point with a laser beam from a position located apart from the processing point by using a laser beam having a long focal length.
Conventionally, in the remote laser processing, a laser beam spinner (Laser Beam Spinner, laser processing head) which controls the irradiation position of the laser beam by rocking two mirrors is used, as described in PTL 1.
A description of conventional laser beam spinner 900 will be given with reference to FIG. 10. FIG. 10 is a cross-sectional view showing conventional laser beam spinner 900.
Conventional laser beam spinner 900 has housing 901, first rocking mirror 902, second rocking mirror 903, torch nozzle 904, first galvanometer 905, and a second galvanometer (not shown). A laser beam incident on housing 901 is reflected by first rocking mirror 902 and second rocking mirror 903, and is emitted from torch nozzle 904. Beam irradiation point SP in the vicinity of seam JL of workpiece W is irradiated with the laser beam emitted from torch nozzle 904, and the laser welding is performed. At this time, by changing a rotation angle of first rocking mirror 902 by first galvanometer 905, and by changing a rotation angle of second rocking mirror 903 by a second galvanometer (not shown), beam irradiation point SP can be spun or scanned.
Further, PTL 2 describes a laser beam oscillator for reciprocating a spot of the laser beam by rotating a first plane light transmitting plate and a second plane light transmitting plate in opposite directions to each other at the same cycle by a single drive motor.